2.1. Determining plant mating system

When trying to determine a plant mating system,
one can use each of the methods described here as experimental treatments or
select only those that appear most relevant to the plant species of interest.
In all cases, a positive control in which flowers are marked but otherwise left
available for open pollination is necessary to provide a reference for
comparison with the manipulative treatments (Fig. 2). In some cases it is also
necessary to provide a negative control in which flowers are excluded from all
flower visitors for the duration of their dehiscence. It is preferable to reduce
background variation by applying distinct treatments to flowers of the same
inflorescence, branch, or plant depending on flower abundance and size of the
plant.

In
the following sections, the performance of a pollinator is implied by the
field-scale observation of subsequent fruit- or seed-set. It is also
appropriate to measure pollen vectoring capacity at the level of viable pollen
on the bee and pollen deposited by the bee onto the stigma. These techniques
are covered in sections 3.1. and 3.2.

Fig. 2. Open pollination
treatment in soybean plantation: flowers are marked and left open for floral
visitors.